Hello,
when I use decimation master, zBrush keep more or less the polypaint. I would like to get an effect with one color per face (see attached picture). If not possible with zBrush, with which software is it?
Thanx
Polypaint = VertexPaint, no perface effect possible 
You can build such “transfer” inside Houdini. I have no idea how, but seen a lot of similar effects successfully overcame inside Houdini.
Good luck!